Individual variability in the cytoarchitectonics of anterior limbic field 24 in the human brain.

The aim of the present work was to identify the main cytoarchitectonic characteristics of individual variability in anterior limbic field 24 in the left and right hemispheres of the human brain using state-of-the-art morphometric analysis methods. Computerized morphometric analysis was used to measure neuron profile areas in layers III and V of subfield 24c of the anterior limbic area of the cortex of the human brain, with assessment of the percentage composition of neurons in terms of this parameter, along with the total neuron fraction (proportion of microscope field occupied by neurons). These studies demonstrated significant individual variability in these characteristics, with asymmetry in the left and right hemispheres.

Serotoninergic mechanisms of the effects of neurotensin on passive avoidance behavior in rats.

The aim of the present work was to identify the features of the actions of neurotensin on administration into the substantia nigra or dorsal cervical nucleus on the reproduction of passive avoidance reactions in rats. The results showed that the action of neurotensin administered into the substantia nigra was accompanied by sharp reductions in passive avoidance reactions, while administration into the dorsal cervical nucleus, conversely, led to increases in these reactions and slowing of their extinction. The effects of microinjections of the serotonin 5-HT(1A) receptor agonist 8-hydroxydipropylaminotetraline (8-OH-DPAT) into these brain structures were analogous to the effects of neurotensin.

Primary structural modules of the dorsal nuclei of the thalamus and motor cortex in humans.

The aim of the present work was to study the primary structure of the modular organization of neurons in the dorsal nucleus of the thalamus (ventral anterior, ventral lateral, anterior ventral, anterior medial, anterior dorsal, medial, reticular) and motor cortex (fields 4 and 6) in humans by the Nissl, Kluver-Barrera, and Golgi silver nitrate impregnation methods. These studies showed that neurons in the dorsal nuclei of the thalamus and the motor cortex are organized as small groups and short chains fulfilling defined criteria. These neuronal complexes, forming individual structural units, were termed primary structural modules.

A common system of sparsely-branched projection (reticular) NADPH-diaphorase neurons in formations of densely-branched cells in the human forebrain.

Morphometric studies of human forebrain formations composed of densely branched cells - the entorhinal cortex, the basolateral amygdala, the nucleus accumbens, the striatum, and the dorsal thalamus - were performed using nine parameters, with statistical analysis of the resulting data; measurements addressed the major projection-type densely branched and sparsely branched reticular neurons (scattered reticular and marginal reticular cells of the dorsal thalamus) stained by the Golgi method and with NADPH-diaphorase. Scattered reticular cells in the various formations showed no differences in any of the nine measures, while there were significant differences (in 5-7 measures, apart from one comparison, where there were differences in two measures) in their major projection-type densely branched cells. Scattered reticular and main projection-type densely branched neurons in each formation differed in terms of 7-9 measures.

Neuronal organization of the reticular nucleus of the thalamus in adult humans.

The neuronal composition of the thalamic reticular nucleus was studied in serial sections of the sagittal and frontal projections impregnated with silver nitrate by the Golgi method. The neuronal composition of the reticular nucleus of the human thalamus was wider than has previously been described in animals and humans. This nucleus, apart from two types of large, sparsely branched, long-dendrite, reticular, aspiny, neurons, i.

Sexual dimorphism of neuroglial relationships in the frontal fields of the human brain.

Cytoglioarchitectonic and quantitative methods were used to study the characteristics of neuroglial relationships in fields in the frontal areas of the male and female brains. Series of frontal paraffin sections of thickness 20 microm stained by the Nissl method were used to study fields 8, 12, 47, and 10. In layers III and V of the right and left hemispheres, the densities of pyramidal neurons (N), satellite gliocytes (SG), and N surrounded by SG (SN) per 0.

Spontaneous activity and rhythm assimilation reactions in baby rabbit hippocampal neurons during learning: age-related characteristics.

The neural mechanisms of the age-related characteristics of memory formation were studied in experiments based on a model providing an analog of a conditioned reflex to time: trace assimilation of the rhythm with which neurons in hippocampal field CA1 were stimulated, in rabbits aged 1-4 weeks and 5-6 months. Stages of changes in neuron spike activity characteristic for developing animals were described. In animals studied one week after birth, there was a predominance of silent cells and cells with low spontaneous activity.

Ultrastructure of the sensorimotor cortex of pubertal offspring of alcoholic male rats.

The ultrastructure of neurons, astrocytes, and capillaries in the sensorimotor cortex of three-month-old offspring of alcoholic male rats (8 g/kg of 50% alcohol solution daily for four weeks) was studied. Apart from signs of delayed maturation of nerve and glial cell processes, some cortical areas showed destructive changes affecting a proportion of neurons along with elements of compensatory-adaptive processes in some nerve cells. Membrane and myelin-like intranuclear inclusions and changes in the Golgi complex were characteristic features of the damage to populations of cortical neurons.

NADPH-diaphorase-positive cells in the thalamic nuclei and internal capsule in humans.

The nuclei of the dorsal thalamus and reticular nucleus in humans were found to contain separated NADPH-diaphorase (NADPH-d)-positive neurons. Staining of NADPH-d-positive neurons and all their processes, along with previous studies of neurons in the nuclei of the dorsal thalamus based on the Golgi method, allowed the type of these cells to be identified as sparsely branched. The main, densely branched, efferent neurons did not contain NADPH-d.

Characteristics of the development of the sensorimotor cortex in rats aged 7-8 days in roller cultures of free-floating brain slices.

The development and formation of the neuronal architectonics of organotypic structures of the sensorimotor cortex in rats aged 7-8 days were studied in roller cultures. Free-floating slices were cultured for 2-3 weeks. Serial paraffin sections of cultured tissue were stained with fast cresyl violet as described by Nissl.

Aftereffects of microinjections of neurotensin into the substantia nigra of the brain on conditioned motor responses in rats with lesions to serotoninergic neurons.

The effects of neurotensin microinjections into the substantia nigra of the brain on the performance of motor reactions in response to positive (food reinforcement) and negative (unreinforced) conditioned signals were studied, along with the characteristic aftereffects of these microinjections in rats with lesions to serotoninergic neurons in the dorsal cervical nucleus. Lesions were produced by local administration of the selective neurotoxin 5,7-dihydroxytryptamine. Microinjections of neurotensin were found to weaken the disinhibitory effects of neurotoxin on extinction of intersignal responses and extinction of conditioned motor reactions in response to presentation of negative stimuli, but to have no marked effect on the performance of reactions evoked by positive conditioned signals.

Structural-functional organization of neurons in the cerebral cortex of rats with different levels of resistance to emotional stress in conditions of exposure to delta sleep-inducing peptide.

Wistar rats with different levels of resistance to emotional stress (ES) were subjected to stress and brain sections stained with Nissl cresyl violet were used for quantitative analysis of the structural organization of neurons in layer V of the sensorimotor cortex. Some animals received delta sleep-inducing peptide (DSIP) 1 h before stress. Control ES-susceptible rats, as compared with resistant rats, had lower levels of normochromic and moderately hypochromic neurons.

Characteristics of the actions of neurotensin on motor reactions in rats in response to positive and negative conditioned signals.

This study addressed the effects of microinjections of neurotensin into the caudate nucleus and substantia nigra on the performance of motor reactions in response to positive and negative conditioned signals, as well as the post-effects of microinjections in subsequent experiments. Neurotensin had positive effects on the extinction of non-reinforced motor reactions. Neurotensin had no effect on the number of motor responses to the non-reinforced signal, though the number decreased in subsequent experiments.

The role of the substantia nigra in cognitive activity in cats.

The role of the substantia nigra in cognitive processes of different levels of complexity was studied using an original method. Neurosurgical or neurochemical exclusion of the substantia nigra in cats led to significant impairment of conditioned reflex activity, generalization and abstraction processes; these recovered with pharmacological treatment directed to the dopaminergic system, with partial recovery after treatment directed to the GABAergic and cholinergic systems. Treatment directed to the serotoninergic system was ineffective.

The action of mexidol on the state of conditioned reflex activity after traumatic brain lesions.

It is demonstrated that even partial damage to the hippocampus is accompanied by impairments to counting time intervals lasting several months (1200-1500 presentations) without alteration of other complex conditioned reflex responses. After treatment with mexidol, which has a wide spectrum of actions, paticularly antioxidant. antihypoxic, and antistress, rats showed a normal process of acquisition of a conditioned reflex to time.

Comparison of the cholinergic system in neocortical field Ep in cats with strong and weak cognitive abilities.

Comparative analysis of the cholinergic system of the neocortex, consisting of the terminals of neurons from the magnocellular basal nuclei and intracortical neurons, in cats with strong and weak abilities to solve abstraction and generalization tasks was performed by isolating subfractions of synaptic membranes and synaptoplasm from "light" (C) and "heavy" (D) synaptosomes from associative field Ep and measuring choline acetyltransferase and acetylcholinesterase activities, protein content, and sulfhydryl group concentrations. These experiments showed that all measures were significantly lower in subfractions from C synaptosomes from cats with strong cognitive abilities. This leads to the conclusion that relatively small numbers of cholinergic synapses form in field Ep of the brains of cats with strong cognitive abilities, while their location in the C fraction demonstrates that they correspond to neurons of the magnocellular basal nuclei.

The effects of microinjection of neurotensin into the caudate nucleus of the rat brain on the performance and extinction of a conditioned motor reflex.

The studies reported here demonstrate that microinjection of neurotensin into the caudate nucleus of the rat brain facilitated extinction of a conditioned motor reflex with reinforcement provided by drinking. Neurotensin had positive effects on the process of post-extinction inhibition in subsequent experiments. Neurotensin microinjections had no marked effect on the performance of the conditioned reflex, though it weakened the emotional tension of the animals in an "open field" test.

Decreases in Ca2+-dependent K+-currents due to cyclic guanosine monophosphate are not dependent on phosphorylation.

Two-microelectrode voltage clamping experiments were performed on isolated snail neurons to measure the Ca2+-dependent. potential-dependent K+ current (I(C)), with assessment of the effects of penetrating cGMP analogs on this current - dibutyryl cGMP (dcGMP) and 8-Br-cGMP. Both of these penetrating cGMP analogs rapidly and reversibly decreased the amplitude of I(C).

[Immunohistochemical study of apoptosis in the cells of experimental injured spinal cord].

We studied the temporal and spatial profile of apoptosis following acute spinal cord (SC) injury in rats and influence of chicken yolk transplantation on the programmed cell death. 18 female rats were subjected to complete SC transsection with removal of three millimeters of the SC at the level of the ninth thoracic vertebra. The gap was filled with denaturated chicken yolk in 9 animals.